The evolution of the NFL:
Take a look at how the NFL has evolved from its humble roots, and the efforts being made to ensure it continues to grow.

"I'm actually improving every week," the New England Patriots tight end told WAAF-FM Radio on Tuesday, per ESPN.com. "It's feeling good and coming along very well."

Gronk said he joined his team for voluntary workouts, which started last week, and has continued his long rehab following January surgery.

One of the best playmakers in the NFL deflected questions about whether or not he will be ready for the Sept. 7 season opener.

"Oh man, that's too far away," Gronkowski said. "I'm just improving every day right now. I'm working hard every day to put myself in the best situation so that I'm ready."

Given Gronkowski's injury history and the rehab schedule for ACL repairs, the Patriots aren't likely to push their best pass-catcher onto the field too soon. In New England it's about winning in January, not September. Having a healthy Gronk by the time the calendar flips is the priority.